Hm, I think it's even more appropriate then, to have an herbal class, with herbs, at events. People need educating, and as long as you check with your students before opening each jar, it should be okay. One of our earliest classes at Novice Schola was on herbs and making salves -- awesome class. One of the essential oils was rosemary which, even if you're not allergic, is something that shouldn't touch skin undiluted -- people were warned, and everything was fine. Having it there led to a good discussion on allergies, in fact, and everyone learned not to make assumptions that just because something is natural, doesn't mean it's safe.